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MISSION 29P
What is Comet 29P?
This comet (aka 29P/Schwassmann-Wachmann 1) is the most observable that exists and yet we understand very little about it. It is the second-most active body in our Solar System, after Jupiter's moon, Io, in that its level of volcanism is engendered by tidal interactions with the planet. The Comet Section has therefore launched this special project to ensure that our understanding of it is much improved such that it becomes the most observed comet that we know of.
This mysterious object is temporarily locked in its present near-circular orbit by the gravity of the giant planets, Jupiter and Saturn. Located at a mean heliocentric distance of 6.0 au, 29P describes an orbit around the Sun every 14.7 years or so, with a perihelion distance of 5.7 au and aphelion of 6.3 au. Because it never approaches the Sun closely, it never exhibits a distinctive tail, i.e. quite unlike most people’s idea of a comet. But like Jupiter and Saturn, the comet is observable during most of each year apart from the couple of months it spends in solar conjunction. Current location in the JPL Small-Body Database Browser.
Intensive observations have been underway since 2014 when the mini-outburst phenomenon was discovered, i.e. weak outbursts not exceeeding 1.0 mag in amplitude. The following set of plots show its behaviour during its six 2014-1019 apparitions (click on the image to obtain larger views):
So what can you do as an observer?
First if you want to capture images that can be used to perform photometry then do consult the Observing Tutorial.
Currently Richard Miles coordinates the observing campaign so please direct any queries to him. The main objectives are:
1. Detect any new outburst as soon as possible after it has taken place so that we can (a) determine the time of the event, and (b) initiate 'target of opportunity' images with the 2.0-m Faulkes Telescopes to study the resulting expanding coma.
2. Measure the brightness of the inner coma and determine (a) the maximum brightness of each outburst, and (b) follow its subsequent decline photometrically.
3. Establish a long-term archive of: (a) its photometric lightcurve (intensive observations began in 2014); (b) a high-precision astrometry archive (so its orbit is precisely known for the prediction of stellar occultations); and (c) archive images series depicting the development of the expanding coma after each significant outburst
By recording its characteristics in this way it is hoped that we can elucidate the true nature of this object
Current Status and Latest Observations:
A medium-strength outburst of amplitude 1.45 magnitudes took place on March 31, first evident from images taken by Patrick Wiggins and confirmed by Luca Buzzi. Here's the best estimate of the timing:
**Outburst at 2021 03 31.48 +/-0.27 17.05R => 15.60R
See more details in observations listed later.
Prior to this relatively strong outburst, two very weak mini-outbursts occurred during March. They both were of just 0.11 magnitudes amplitude reaching 16.9R:
With many dedicated observers following 29P, we get a much more reliable evaluation of small brightness changes even though it is now 17th magnitude. This is a good demonstration of the benefit of having more observers. For the first 11 days of coverage, the intrinsic trend due to varying distance and phase angle is expected to be a fade of 0.018 mag. However on March 17.46 +/-0.28 there looks to have been a step-change of 0.11 mag (red datapoints). This is the smallest mini-outburst that we have detected.
Recent images:
The following two images were taken at almost the same time. The one on the right is unfiltered. You can see extra coma further from the nucleus than can be seen in the r'-filtered image on the left. The reason for this may be that the nucleus has been almost quiescent during the past 30 days with little debris ejected far into space since most of it falls back. So what does escape is gas from sublimating hypervolatile ices and it is the emission lines from the gas that adds to the coma brightness far from the nucleus.
We know that the main gas species is carbon monoxide and most CO+ emission lines appear at wavelengths shorter than the passband of the r' filter (550-690 nm). Also nitrogen (N2+) emission is mostly at the blue end of the spectrum Unfiltered images should pick up these faint gaseous emissions as can be seen in Jean-François Soulier's image on the right.
See plot below also showing how data from several observers monitoring the comet allows us to detect small outbursts. We've had a couple of such events in the last two weeks or so as shown in these plots:
**Outburst at 2021 03 31.72 +/-0.08 17.05R => 15.60R
Mini-outburst at 2021 03 24.00 +/-0.11 17.01R => 16.90R
Mini-outburst at 2021 03 17.5 +/-0.3 17.04R => 16.93R
Mini-outburst at 2021 03 04.5 +/-0.5 17.04R => 16.87R
Mini-outburst at 2021 02 27.3 +/-0.4 17.08R => 16.93R
Mini-outburst at 2021 02 08.97 +/-0.11 16.65R => 16.45R
Mini-outburst at 2021 02 06.93 +/-0.11 16.90R => 16.65R
Mini-outburst at 2021 01 24.38 +/-0.35 16.55R => 16.35R
!!! Strong outburst at 2021 January 14.04 +/-0.01 17.0R => 14.7R !!!
Mini-outburst at 2021 January 08.49 +/-0.22 16.93R => 16.80R
Mini-outburst at 2021 January 06.15 +/-0.06 16.95R => 16.75R
Mini-outburst at 2020 December 21.98 +/-0.08 16.70R => 16.50R
Mini-outburst at 2020 December 11.97 +/-0.07 16.35R => 16.10R
!!! VERY STRONG OUTBURST on 2020 November 19.763±0.001 from 16.2R to 13.2 R!!!
Thanks to Jean-François Soulier (L27, Haute-Provence, France) and Nick James (970, Chelmsford, UK) who independently discovered the comet going into outburst. Thanks to Nick's timely alert we have obtained the best coverage ever of one of this comet's outbursts. Here is a plot of the data from L27 showing the outburst lightcurve analysed in terms of the G magnitude using a 10" radius photometric aperture. A video of this outburst has been prepared by Jean-François.
Another outburst also took place less than 6 days later on 2020 November 25.45±0.24 with the magnitude going from 15.3R to 14.3R
29P reached opposition on November 6 and so now appears in the early evening sky making it an excellent target for northern hemisphere observers. Located in Aries at a declination of +24 degrees, the comet is visible for a couple of hours after sunset between now and the end of April.
Here below is the latest light-curve showing its activity during this apparition up until April 04. Click on the plot if you want to see the full-size image. There have been two very strong outbursts: one on July 26 and a second on November 19, minute-by-minute coverage of which we have achieved largely thanks to Jean-François Soulier's dedicated 29PREMOTE observatory. More on those findings later. Jean-François was also successful in catching the start of the August 22 event. In all we now have outburst lightcurves spanning the first few critical hours for FOUR events namely in 2017, 2019 and 2020(2).
In addition to strong outbursts, the nucleus has exhibited at least 23 mini-outbursts some of which have been so weak that there have been 5 instances where a large fraction of the ejecta have, after several days, fallen back onto the nucleus. This happens because the nucleus is very large (approx. 64 km across) and so has a relatively high gravity and high escape velocity (approx. 20-25 m/s). Our detailed observations are revealing this collapse of the inner coma - a behaviour unique to this body! We might indeed consider 29P not to be a comet but instead a unique Transition Object that was once a TNO.
Recent observational data in MPC format
(Date, RA, Dec, Magnitude, Observatory Code, Photometric aperture in arcsec, Comments)
0029P KC2021 03 29.85904 02 52 58.69 +25 03 01.1 16.96R J77
0029P KC2021 03 29.88441 02 52 59.90 +25 03 03.4 17.02R J77
0029P KC2021 03 29.89264 02 53 00.12 +25 03 05.9 16.94R J77
0029P KC2021 03 30.82356 02 53 43.08 +25 05 12.6 17.05R 204 5.6
0029P KC2021 03 30.83445 02 53 43.58 +25 05 13.7 16.95N L27 6.6
0029P KC2021 03 30.83986 02 53 43.85 +25 05 14.6 16.98N L27
0029P KC2021 03 31.82733 02 54 29.58 +25 07 30.5 15.77R 204 5.6
0029P C2021 04 01.12731 02 54 43.52 +25 08 12.2 15.60R 718
0029P C2021 04 01.12885 02 54 43.59 +25 08 12.6 15.58R 718 5.2
0029P C2021 04 01.13038 02 54 43.63 +25 08 12.5 15.58R 718
0029P C2021 04 01.13190 02 54 43.72 +25 08 12.9 15.59R 718
0029P KC2021 04 01.81795 02 55 15.73 +25 09 48.3 15.69N L27 6.6
0029P KC2021 04 01.83647 02 55 16.58 +25 09 51.2 15.72N L27
0029P KC2021 04 01.84916 02 55 17.20 +25 09 52.1 15.57R I81
0029P KC2021 04 01.85274 02 55 17.38 +25 09 52.9 15.53R I81
0029P KC2021 04 01.85634 02 55 17.53 +25 09 53.1 15.55R I81 5.2
0029P KC2021 04 01.85994 02 55 17.69 +25 09 53.8 15.59R I81
0029P KC2021 04 02.13335 02 55 30.43 +25 10 32.2 15.53R 718
0029P KC2021 04 02.13488 02 55 30.54 +25 10 32.7 15.48R 718
0029P KC2021 04 02.13641 02 55 30.59 +25 10 33.0 15.52R 718
0029P KC2021 04 02.82072 02 56 02.67 +25 12 08.6 15.72N L27 6.6 3x60s
0029P KC2021 04 02.83924 02 56 03.50 +25 12 10.8 15.78N L27
0029P KC2021 04 02.86346 02 56 04.71 +25 12 14.3 15.52R I81 5.2 3x60s
0029P KC2021 04 02.86561 02 56 04.80 +25 12 14.5 15.54R I81
0029P C2021 04 03.11759 02 56 16.62 +25 12 50.3 15.50R 718
0029P C2021 04 03.11912 02 56 16.66 +25 12 50.2 15.59R 718 5.2
0029P C2021 04 03.12065 02 56 16.79 +25 12 51.2 15.54R 718
0029P C2021 04 03.12218 02 56 16.81 +25 12 50.9 15.58R 718
0029P KC2021 04 03.83806 02 56 50.57 +25 14 32.3 15.69R C10 6.5
0029P KC2021 04 03.85744 02 56 51.48 +25 14 34.7 15.75R C10
0029P KC2021 04 03.84325 02 56 50.76 +25 14 33.1 15.69R Z10 5.5 3x60s
0029P KC2021 04 03.84556 02 56 50.91 +25 14 33.1 15.75R Z10
0029P C2021 04 04.11900 02 57 03.84 +25 15 11.0 15.60R 718 5.2
0029P C2021 04 04.12053 02 57 03.93 +25 15 12.5 15.70R 718
0029P KC2021 04 04.82564 02 57 37.25 +25 16 51.9 15.73N L27 6.6 field star
0029P KC2021 04 04.84369 02 57 38.19 +25 16 55.9 15.85N L27 6.6
0029P KC2021 04 04.87819 02 57 39.71 +25 17 01.0 16.04R J77 5.44 12x60s r
0029P C2021 04 05.12153 02 57 51.28 +25 17 35.3 15.95R 718 5.2
0029P KC2021 04 05.82637 02 58 24.89 +25 19 16.9 15.88N L27 6.6
0029P KC2021 04 05.84443 02 58 25.73 +25 19 19.1 16.09N L27
0029P KC2021 04 05.86742 02 58 26.74 +25 19 23.4 16.24R J77
0029P KC2021 04 05.87339 02 58 27.11 +25 19 22.9 16.22R J77 5.44 8x60s r'
0029P KC2021 04 06.82952 02 59 12.84 +25 21 41.1 15.94N L27 6.6 poor seeing
0029P KC2021 04 08.81722 03 00 48.46 +25 26 31.7 16.25R 204 5.6
0029P KC2021 04 08.82829 03 00 49.02 +25 26 33.1 16.56N L27 6.6
0029P KC2021 04 08.83912 03 00 49.50 +25 26 34.9 16.64N L27
0029P KC2021 04 09.89725 03 01 40.74 +25 29 09.1 16.74R I81
0029P KC2021 04 10.87836 03 02 28.59 +25 31 36.1 16.47R I81
0029P KC2021 04 10.88050 03 02 28.69 +25 31 36.7 16.53R I81 5.2 3x60s
0029P KC2021 04 10.88263 03 02 28.80 +25 31 36.5 16.48R I81
0029P KC2021 04 11.86228 03 03 16.66 +25 34 03.7 16.58R J77 5.44 10x60s
0029P KC2021 04 11.86976 03 03 17.02 +25 34 04.8 16.64R J77
0029P KC2021 04 12.82244 03 04 03.88 +25 36 29.2 16.74N L27 6.6
0029P KC2021 04 12.82786 03 04 04.20 +25 36 30.6 16.78N L27
List of Observers:
List of Observatory Codes / Observers / Instruments / Photometric aperture in arcsec
N.B. This is a comprehensive list of observatories/people whose work has contributed to the current Observing Campaign, which began in 2014 February.
203 G. Galli, S. Foglia Italy 0.36-m f/5.76 Schmidt-Cassegrain 5.5
204 L. Buzzi, A. Aletti Italy 0.36-m f/6.5 reflector 4.8/6.0; Italy 0.84-m f/3.5 reflector 5.6
213 R. Naves, M. Campas Spain 0.30-m f/10 Schmidt-Cassegrain 10.0 square; Spain 0.30-m f/9 Schmidt-Cassegrain 5.4
323 P. Camilleri, J. Oey, R. Miles Australia 0.40-m f/5 reflector (Perth)
718 P. Wiggins Utah, USA 0.35-m f/7 Schmidt-Cassegrain 5.2
970 N. James England 0.28-m f/10 Schmidt-Cassegrain 5.2/5.8 check
A06 E. Cortes Spain 0.25-m f/3.6 Schmidt-Cassegrain 10.0 square
A77 J.-F. Soulier, F. Kugel France 0.20-m f/4 Newtonian reflector 5.0/6.6
B74 J. M. Bosch Spain 0.40-m f/10 Schmidt-Cassegrain 10.0 square
B96 E. Bryssinck Belgium 0.4-m f/3.8 astrograph 5.0
C10 J.-F. Soulier France 0.30-m f/3.8 Newtonian reflector 6.5, 4.9
C35 J. Aledo Spain 0.4-m f/3.4 Reflector 10.0 square
C42 Q. Ye (Zwicky Transient Facility) Xingming, China 0.50-m ?
C77 A. Mantero Italy 0.25-m f/4 Reflector 6.7
C90 L. Tremosa Spain 0.30-m f/5 reflector 10.0 square
E94 J. Drummond N.Zealand 0.35-m f/10 Schmidt-Cassegrain 5.9; 0.41-m f/5.2 Newtonian 7.2; 0.41-m f/4.5 Newtonian 6.0
G40 J. Tuten Canary Isles 0.43-m f/6.8 Dall-Kirkham 5.0
H06 N. James New Mexico 0.43-m f/4.5 5.8; A. Watkins New Mexico 0.43-m f/4.5 5.8
I41 Q. Ye (Zwicky Transient Facility) Palomar, USA 1.20-m f/2.5
I64 A. Jones England 0.19-m f/5.2 Mak-Newt + Rc filter 5.6
I81 D. Buczynski Scotland 0.35-m f/6 Schmidt-Cassegrain 5.2
I88 J. Carrillo Spain 0.36-m f/5 reflector 10.0 square
J01 J. Gonzalez Spain 0.15-m f/6 Ritchey-Chretien 10.0 square
J22 K. Hills La Palma 0.50-m f/2.9 astrograph 5.9, 10.0 square
J24 J. F. Hernandez Spain 0.4-m f/10 Schmidt-Cassegrain 10.0 square
J38 F. Garcia Spain 0.25-m f/8.1 Ritchey-Chretien 10.0 square
J47 G. Muler Lanzarote 0.30-m Schmdt-Cassegrain 6.1
J77 R. Miles England 0.35-m f/8 Schmidt-Cassegrain + r' 5.4 also V, B, Clear
K01 A. Watkins England 0.35-m f/7.7 Schmidt-Cassegrain 6.2
K02 P. Carson England 0.32-m f/5.4 Dall-Kirkham 5.5/6.5
K14 M. Morales Spain 0.25-m f/5 Newtonian 5.7, 10.0 square
L27 J.-F. Soulier France 0.20-m f/4 Newtonian reflector 6.5, 5.0
Q38 M. Mattiazzo Australia 0.28-m f/6.3 Schmidt-Cassegrain 5.5
Q67 P. Camilleri, J. Oey, R. Miles Australia 0.32-m F/8.8 RCOS 5.5
Q68 P. Camilleri, J. Oey, H. Williams Australia 0.30-m f/3.0 reflector 7.4; P. Camilleri, J. Oey Australia 0.34-m f/5.9 SCT
W88 K. Breedlove, J. Tuten, A. Hale Chile 0.35-m f/11 Schmidt-Cassegrain (Slooh) ???
W96 J.-F.Soulier, A.Maury, J.-B. de Vanssay Chile 0.4-m f/5.2 Ritchey-Chretien 6.4
Z08 E. Bryssinck Oria, Spain 0.70-m f/6 reflector (remote) 5.2 r'
Z10 P. Carson Spain 0.32-m f/5.4 Dall-Kirkham 5.5
Z30 D. Storey England 0.35-m Ritchey-Chretien 5.9
Z39 A. Acosta Lanzarote 0.23-m Schmidt-Cassegrain 10.0 square
Z42 J. Savage England 0.35-m f/7.7 Schmidt-Cassegrain + V 5.5, 7.9
Z74 F. Soldan Spain 0.20-m f/6.7 Schmidt-Cassegrain 10.0 square
Z80 G. Wells, D. Bamberger England 0.25-m f/8 Ritchey-Chretien 6.7
Z85 T. Angel Spain 0.35-m f/11 Schmidt-Cassegrain 5.6
XXX C.S. Morris California, USA 0.406-m f/6.8 Schmidt-Cassegrain 4.84
Las Cumbres Observatory / Faulkes Telescope Project (R. Miles, A. Hale):
A major contribution to this '24/7' comet monitoring activity have been the observations from the Las Cumbres Observatoryglobal network of telescopes. Access to this network has been made available thanks to the Dill Faulkes Education Trust, and to Dr Paul Roche of the Faulkes Telescope Project based at Cardiff University, Wales assisted by Alison Tripp.
E10 coj 2m0a Siding Spring-FT South 2.0-m f/10 Ritchey-Chretien 5.4
F65 ogg 2m0a Haleakala-FT North 2.0-m f/10 Ritchey-Chretien 5.4
K91 cpt Sutherland A S. Africa 1.0-m f/8 Ritchey-Chretien 5.5
K92 cpt Sutherland B S. Africa 1.0-m f/8 Ritchey-Chretien 5.5
K93 cpt Sutherland C S. Africa 1.0-m f/8 Ritchey-Chretien 5.5
Q63 coj Siding Spring A Australia 1.0-m f/8 Ritchey-Chretien 5.5
Q64 coj Siding Spring B Australia 1.0-m f/8 Ritchey-Chretien 5.5
V37 elp McDonald Observatory A Texas, USA